Speaker
Description
Positronium (Ps), an exotic atom composed of an electron and its antiparticle, the positron, serves as an excellent system for fundamental physics investigations. Its unique composition of light leptons makes it an ideal system for testing Quantum Electrodynamics (QED) and probing physics beyond the Standard Model. A key aspect of such studies involves comparing calculated energy intervals with precise measurements, often achieved through laser spectroscopy. Because of the current situation that measured precision is inferior to that of theory, breakthroughs on experimental side are required; one of which is Ps cooling for both precision and accuracy.
In the presentation, we will report the demonstration of one-dimensional chirp cooling of Ps [1]. By subjecting Ps to an optimized laser system developed in our laboratory [2], we achieved an unprecedentedly low temperature of approximately 1 K. This temperature is two orders of magnitude colder than what conventional cooling methods can achieve. The laser system was designed to maximize the number of Ps atoms with zero velocity along the cooling axis. Numerical simulations, rigorously modeling the Ps-laser interaction, allowed us to reasonably reproduce the resulting velocity distribution after laser cooling. We will also discuss about improvements for cooling the majority of Ps atoms thermally emitted [3], three-dimensional laser cooling, and prospects for precision spectroscopy powered by laser-cooled Ps.
References
[1] K. Shu et al., arXiv:2310.08761.
[2] K. Shu et al., Phys. Rev. A 109, 043520 (2024)..
[3] L. T. Glöggler et al. (AEḡIS Collaboration), Phys. Rev. Lett. 132, 083402 (2024).
